S-video cable length???? [Newbie Post]

Guest

I have just bought a Nad T550 DVD player and am v pleased so far, my question may be basic stuff for you guys but I am a newbie, so be gentle please!
OK, because of the lack of Scart connections on the old TV I am using [a new TV next year hopefully] I have had to connect to the TV using good quality S-video cable, so far so good. I am getting a great picture.
The sound is handled by an elderly Technics stereo amp connected direct to the DVD by good q phono leads.
The problem that I have is that the sound appears to be too slow,
i.e. someone speaks, their mouth moves, the sound appears a fraction of a second later. It is hardly noticable but once you know it's there.........
My S-video cable is 1.5 metres long
Phono leads are 5 metres long
Could the length of the cables be the problem, I have tried a scart lead as comparison and the sound problem seems to go away.
Any help appreciated.
Kind Regards..........Tony